 Okay, so I've got a money back guarantee here on this talk, and this is the point where my lawyer friends remind me that this is a free event, so there's no money back. You're not getting anything back from me. I know. So you can leave. It's fine. We're going to talk about ET. We're going to go there. We're going to talk about aliens. This is my preview of the whole talk here, my little pictographic representation we're going to talk about. So let me tell you what I'm going to tell you so that after I tell you, you'll remember that I told you. The idea here, we want to get people interested in this problem. In this case, you are people, and so I want to get you interested in this problem because we need support, and in grown-up land, support means money, right? This is what grown-ups reference to be support. If we have people and we have support, then we will be able to use fancy computers and algorithms to use telescopes to search for signals that might originate from aliens. That's where we're going. Before we go there, I want to reflect for a minute. It seems like a good moment to reflect standing up here. Two and a half years ago, exactly, I was standing right here and in this picture. I had shorter hair. I gave a talk at Astronomy on TAP. It's been a while. I gave a talk about misinformation in science, trust in science, trust in media, BS on Twitter. I tried to end that talk on a hopeful note. You don't want to bum people out while they're drinking beer. I tried to end this talk on a hopeful note saying if we pitch it in together, we can restore trust. We can get rid of this spam that populates Twitter. We can get people to trust vaccines and trust the weathermen. I was wrong. If anything, the last two and a half years have shown me is this is a much larger problem than we speculated together here at Astronomy on TAP. I love this emoji. This is a weary face. I use it more often than I thought I would. This is my bad. I thought we had this under control. Obviously, we did not. Sorry about that. Instead, tonight, I'm going to go on totally, I'm going to ride this success and I'm going to make an even better prediction here about aliens. That seems like a safe bet. We're going to talk about the search for extraterrestrial intelligence. This is not a topic that a lot of astronomers like to talk about. It's a topic that the internet really likes and that the history channel really likes with people who say aliens. So thank you for roasting me there, Tyler. This is known as SETI, the search for extraterrestrial intelligence. You're all smart. SETI, SETI. We're going to talk about SETI. And I'm going to make a bold prediction to you here. That's not that bold. I'm going to make a bold prediction that in the next 10 years, we're going to do more SETI, more searching for aliens than we've done ever. Certainly in the last 60 years, which we would call the modern astronomy era, we're going to do more in the next 10 than anybody has ever done in all of history. We're going to make the first serious attempt at this. This is my bold prediction because I'm trying to will this to happen. I'm trying to sell this to you so that you'll support us. SETI is not the search for little green men. Not the search for Martians. I mean it kind of is or else we wouldn't be talking about it. But it's not. SETI is a search for life. SETI is looking up and wondering. SETI is what my inner 8-year-old reminds me of when I do this job. It is a search for life. Now astronomy loves the search for life. NASA loves the search for life. Totally sellable. Congress will fund it. It's great. We launched JDBS T. It's all about it. It's great because they have this great branding. They have this great branding of this thing called biosignatures. The whole field of astrobiology is looking for biosignatures. Signatures of life, of biology. This is like looking for cow farts in nearby planet atmospheres. Methane, things like that. If you find methane or phosphine or whatever, there must be biology going on. And thus life. And thus, because of cow farts, we're not alone. It's great branding. SETI has a branding problem, I think, mainly. I'm not the only one thinking this. And about 10 years ago, we got a little better at this. And we invented our own term called technosignatures. And I love this term. We've already seen it. We've seen it today in the trivia. Technosignatures. Signatures of life that originate from technology. Now, a UFO landing in the middle of downtown would be a really strong technosignature. We would obviously be like, well, that's something. We would get that. But there's a lot of other things as the trivia alluded to. The night sky glow from city lights, cow farts are not one of them. But if you could see the cows, if you could see the ranches from space, lights from cities, radio emissions from airports, these are all technosignatures. Here's the bummer part. SETI is almost totally unsupported in the United States. And whoo, whoo, cheer for that. Get out of here. Almost totally unsupported. In terms of topics that we, again, support for grown-ups means money. Topics that the US government, the taxpayers are willing to fund, SETI ranks very low. Fair enough, it doesn't solve a lot of real world problems. But it shouldn't be at the bottom. It shouldn't be zero. And so let's spend a minute to talk a little about history. This guy, Bill Proxmire, is a complicated figure in our history. He was the longest-serving Democrat from the great state of Wisconsin. He had a very white guy thing he liked to do, which is he liked to hand out awards that he invented and given to people and trophies. It's a very self-aggrandizing thing to do. And he handed out these awards he called the Golden Fleece. And the Golden Fleece Awards were things that he thought were fleecing the US taxpayer and we should get rid of. And this became like, you did not want to gold it. Military generals did not like Bill Proxmire's Golden Fleece Award. You did not want one of these because you're funding, but go to zero. And he, in the late 80s, NASA was getting ready to fund a big mission, a big radio survey that was going to be dedicated towards SETI. Like we had done a bunch of work in the 60s and people said, this is a good idea. There's good ideas, there's good science. We can test this. We can do this grand thing and look for a science of life. And Bill Proxmire said, let's not do that. He said, goal and goose for you. This is all gonna go towards this quote here. He says that this is the best argument for chopping NASA's funding to the bone, which is a major bummer. If you're sitting here, there's better than even odds. You like space. Zero NASA funding, not so great. Not a penny for this nutty fantasy, he says. This is not great. Now, again, he's a complicated guy. He voted for the Civil Rights Act. I'm pro-civil rights act, that's great. Carl Sagan got a meeting with him after this and managed to talk him off the proverbial cliff about this and chilled him out. And he said, okay, okay, we'll relent. You can have some of that funding back. And NASA was able to move forward. I just broke their mouth, that's classic. There we go. This is the guy who watches Neil Armstrong, Man on the Moon and says like, ah, that's a bit expensive, right? Like, and then takes a big glass of like warm milk. This is Bill Proxmire. But he chills out. Carl Sagan does his thing, wears his turtleneck, kind of sways him. Yeah, shout out to turtlenecks. Shout out to Carl Sagan too. So about 10 years later in the early 90s, NASA's like, great, okay, we've got some money. We're gonna do this setty thing. We're gonna do it, we're gonna look. We're gonna use radio telescopes. It's gonna be great. And then, Dick Bryan from Nevada says no and puts the big kibosh on it. Layed in the game and kills this Bill and says, this hopefully is the end of Martian hunting season at the taxpayer's expense. And this sucks. Like this effectively not only kills this specific project, but this starts 20 years of NASA and the NSF and all the government agencies not funding SETI. This ruins SETI funding for a generation. And this is a major bummer. From the dude who represents the state that gambles as their number one export. Like, rolling dice is what they do, but this is too high a risk. We can't look up and wonder. This bums me out. And so as a result, it's not entirely true, but as a result, SETI has almost entirely survived on private funding and private initiative. A lot of astronomers with professional funding, i.e. NASA or NSF money, do it on the side. Maybe one paper every year gets published here and there. There have been something like five PhDs ever in like the last 50 years. Five PhDs on SETI as a result. And maybe six this year, because there's no funding. This is a bummer. So I've bummed everybody out. Great, take a drink. Because there's a little bit of hope. There's a little bit of hope on the funding, on the support end. And that is that there have started to be, well, richer private funding people, people who have more money than just, we can pass the hat around. And if you wanna give me 20 bucks to look for aliens, that's great. But that's not gonna go that far. But people with a little bit deeper pockets have been getting interested in the game. And NASA and NSF have actually relented a little bit. And people have talked a little sense into them, saying this is a real thing. We're trying to actually ask real science questions. And so we can measure that success by the number of logos that are showing up across the field. Yeah, it's clearly a major success. So NASA has done Astrobiology Institute. This is not just technosignatures, this is also biosignatures, it's mostly biosignatures, because it has bio in the name. But the fact that NASA's making studying life, it's like number one thing going forward. That's awesome. Biosignatures in NASA, this is good. This gives us a window to look for life through technology. Penn State, a fine institution, has an entire institute now, devoted to this. Berkeley, just down the coast, has an institute related to SETI. The SETI Institute, which evolved from private funding, continues to be a thing. And NASA itself held a technosignature workshop in 2018. Like this is huge. The workshop was sort of thrown together quickly. And actually there's a wonderful paper that came out of it that's super dry and boring. And that's what you want. You want the business of astronomy to be done. You want a good boring report to come out so that we can all think about it. This is good. The number of logos is increasing. As Meredith talked about, a new era of astronomy is here. Here's a really cheesy logo from clip art. The era of computer, you've heard of, and internet, you've probably heard of. These are a new era in astronomy. We just heard in the last talk this amazing survey that's going to map the night sky, all this work in the radio that's going on, and all this being distributed by the internet. This is amazing. And here, I think, is a genuine opportunity. And this is what I'm working on with some students, and this is what I'm here to sell to you today. So here's a review for the last product. The Legacy Survey of Spacing Time, a 10-year mission on the Vera Rubin Observatory. This telescope is eight and a half meters in diameter. Almost 30 feet in diameter. This telescope would fill this tent, just the telescope. And then it's in a giant dome on top of a mountain. This is an amazing, enormous facility. This is a humongous telescope. This puts it in the top five or so telescopes in the whole world, maybe the top eight telescopes in the whole world. It's a massive piece of glass moving around, robotic mapping the sky. Okay, you've got six colors. Astronomers are black and white, interesting, fun fact. And so we've got six colors. We've got basically ultraviolet, blue, green, yellowish, reddish, and near-infrared, something like that. We've got six colors across the most invisible spectrum. It's a 10-year mission, 17 billion stars, mostly in the southern part of the sky. Here's our sky map. And 20 terabytes a night, right? So Meredith and her team are creating this fire hose that we're trying to sip out of that's gonna give us this incredible wealth of data from the Rubin Observatory. I am thrilled about this for every strong reason possible. Specifically, one area that really excites me is the so-called alerts that Rubin will publish. So one of the design specs for Rubin is within 60 seconds of every image being taken. So they've got this camera. I don't know if you appreciated this in that last talk. The camera, the size of the camera is like as tall as I am. Like, it's an massive camera. It is like three feet across. It's humongous camera, the biggest camera in the world. Every, within 60 seconds of the shutter closing on that camera, that image is downloaded, is processed, is compared to an archival reference and anything that has moved or changed or in any way different than that archival image is then cataloged, compared to that catalog and then published to the internet within 60 seconds. This is nuts. This is a true fire hose. 10, one to 10 million of these things going bump in the night every night. This is wild, right? And this is real time, open to essentially everyone. You can drink from the fire hose yourself. I like this image. I like the, this is from a workshop in Tucson a few years ago. I like this rainbow of data coming in and then beaming out to all the other telescopes. The broadcasting out, it reminds me of the rainbow bridge in Thor, which I think is really cute. And I just saw the new trailer for the Thor movie, so that looks cool. So the alert pipeline in particular. Fascinating data set. And so I go back to my prediction. Talk about this massive data set. SETI needs to learn how to use this. SETI traditionally has been radio telescopes for lots of reasons. We have a fire hose that's gonna be broadcasting data every night. We need to learn how to drink from this because this is where the action's happening. The computers are here, the data's here. We need to learn how to use it. We're gonna do more SETI with this data in the next 10 years and it's been done in the past 60. Okay, so what are we looking for? How does SETI work in a modern astronomy context? We're looking for outliers. We're looking for things that are unexplainable. So the boring description is that anything that can't be explained by natural astronomy, this is things that stars do, or natural physics processes. And as a professional astronomer, let me tell you something about stars. They're super duper annoying. Stars do all kinds of noxious things. This is super duper hard. We're looking for lighthouses, right? It's easy to imagine we're looking for a spaceship landing in the middle of the city. That's easy to picture, but that's probably not what's going to happen. But think about a lighthouse. Think about if you were a bird and you saw a lighthouse, you would be like, what is this thing that's blinking at me? I have no context for why it's blinking at me, and yet it's blinking. If you were a sailor, if you just bought a boat today and when sailing and didn't know what a lighthouse was, you'd be like, oh cool, somebody put a strobe light out, and then you would crash into the rocks because you didn't have any frame of reference. But you'd probably be able to intuit that like a person put it out there. If you had a similar level of intelligence technology as the people who built the lighthouse. Think about lighthouses, think about runway landing strips, other things that we do that broadcast lights and information. A lighthouse does not contain an awful lot of information, right? It's not like your phone, it's not Morris code, right? It just goes like blink on, off, on, off. That's all a lighthouse does. It's very simple. If you didn't know what a lighthouse does, that's all it does, it just blinks at you. It's not a incredibly information dense signal. You have to know what you're thinking when you're broadcasting, like, huh, why are they blinking a light at me? Do they want me to come towards them? No, the answer is no. You need to go away from lighthouses. Okay. We're thinking about lighthouses that people might build around stars. Pros and cons here. There's a lot of stars, 17 billion stars is a lot. This is a lot to draw from, I like this. This is job security, lots of stars to search. Good. Again, stars kind of screw balls. Stars change their brightness. Stars blink at us. Stars have other stars that go around them to make them do funny things. Stars age, stars explode, stars have dust. Stars do a bunch of obnoxious things. They're very pesky, they're very obnoxious and they can fool us into thinking of the tricky things that are happening. So it's a pro and a con. We got a lot of them, but they're really obnoxious. We're looking for a needle in a haystack. This is another analogy, right? But it's not a needle in a haystack, right? It's a needle in a haystack made of needles being dumped out of a truck on the highway and you're trying to search for the needle, right? Like, it is a multi-dimensional changing problem with time. It's a very difficult problem. We don't know what this lighthouse is gonna look like, what this runway is gonna look like. We don't know how often we need to look at the space to see the light blink. We don't know how much space we need to look to find the lighthouse. We don't know how faint the lighthouse is or how far away it is or what color the lighthouse bulb is. Is it blue? Is it red? Is it infrared? Is it radio? We don't know. And there's all kinds of other things. There's something like eight or nine dimensions to this haystack that we're searching and we don't know what we're looking for. Jill Tarder is the most famous and impactful study astronomer in the last 50 years. Carl Sagan, good to. Jill Tarder, she likened this problem to studying the Earth's oceans by sampling a cup of water. Like, you hold up your pint glass and that's how much water you have and you're trying to understand the complexity of the Earth's oceans and life within them. That's how much we have searched so far. This is how much of the haystack we have searched of this whole volume. This is an incredible volume to try to infer something from 12 ounces. This is a hard problem. Now, we've gotten better. That was 2000, so 20 years later. We're doing a little better. We have bigger radio telescopes. There's some more private money coming in. NASA's putting a little bit of money into this. We have gotten to something like a hot tub compared to the Earth's oceans. Hot tub good, hot tub good. Like you could catch a fish in a hot tub and like, oh, there's actually life in this thing. Yeah, yeah, I mean you could learn a lot about the oceans with one hot tub's worth of ocean. If you were trying to study whales, you'd be in trouble, right? And so again, what I'm selling here is this idea that we're gonna do an incredible amount of work. We're gonna revolutionize this by studying a swimming pool's worth. This is the revolution we're trying to build. You could actually catch a whale in a swimming pool. I think this is the selling point. With new surveys, with new technology, with software, we think we can get to something like the volume of a swimming pool as compared to the volume of the Earth's ocean. This is still a bleak reality, right? This is a huge haystack we gotta search. And we only have a swimming pool or two's worth of water. That's tough. But it's something, it's the right direction. So we could either be very lucky, right? We could be lucky. Our spaceship could show up and steal a cow in the middle of the city and that could happen on the live stream and people could like it and the algorithm would promote it and then you would see it and maybe believe it. We could, like we have to accept, we could get lucky. Maybe the Vulcans show up. It could happen. But I don't know about you, I'm not feeling especially lucky the last couple of years. So instead, my prediction is this is gonna be really, really hard. And that's okay. We're not afraid of hard problems, right? The search for life, the search for cow farts around nearby stars, that's a hard problem. But we like hard problems. That's what science is about. That's why we look up, right? This is a hard problem. And it might take us a thousand years to do it. But someday we could do it. Okay. So in the last act here, what are we looking for? I'm gonna give you three examples. These are not comprehensive examples. These are three examples that I'm interested in because of the things that I'm working on. There are many ways to search this haystack. Many, many hot tubs worth of water we could imagine sifting through. Three real examples that we're working on. The first I love, because it's so simple and I like simple things, it's looking for disappearing stars. So the idea, as we saw in the trivia, would be aliens build a dyson sphere or some kind of structure of solar panels or something around their star and thus the star appears to disappear. It blinks out of existence. This is good. I mean, I don't know if this is good for the star. But this is good for us because it's an easy signal to search for. It might be a preposterous scenario. I don't know, I'm not an alien. But I can search for this. I can write software to go look at this image from 50 years ago and this image from 10 years ago and say, are all those fuzzy circles in the old image also in the new image? We're good at these kinds of problems. We have algorithms that can tell if there's a cat in this image and in this image. So this is a solvable problem. We can do this in the cloud. I love this because it's so simple and there are some candidates. This is one of the candidates in this paper by BHSVRLA and this star is not in this image. And probably a very mundane thing, right? Probably the star has an eclipse or is a distant star had a flare. There's a lot of reasons why you might find something like this. But it's easy to look for and I like that. We can write an algorithm that does this work for us and we can search through a century's worth of images. This is a cool project. All right, the second one. It's a little more subtle, but it's one that I've been enjoying because I've got a student the last year working on this, so it's really fun. The idea is using a coordinating event to synchronize your lighthouse. So if somebody dropped a glass over here, don't drop a glass, that'd be rude. If you dropped a glass, everybody would look, right? It would get your attention and you'd all look. This is like the game Marco Polo. I could yell Marco and you would yell Polo and I would know where you are and then we would laugh and forget about the colonialism and it would be fine. It's pretty cool. The idea is there's some noteworthy event that happens in the sky. Somebody drops a glass and gets our attention. We're astronomers, we're out here looking. That signal, that information propagates out into space. And other astronomers, aliens, other astronomers also notice this and say, whoa. And they yell Polo or whatever. And they say, hey, maybe I'll see that. And they send their own broadcast out. Meanwhile, this broadcast continues to radiate out and we see it. Eventually we see this event and then eventually we see the transmission from the other star, from the other civilization and we say, whoa. We say, whoa. What I like about this is it forms a triangle, right? There's a simple triangle where the only thing at work here, all these signals travel at the speed of light. Thank you, nature, for the speed of light. It's the same number, no matter which way you go. So this is the speed of light times the distance. This is the speed of light. The distance is all that matters here. And we know how to measure the distance to stars. Because we're astronomers, see, that's what we do. And so we know, if we see a noteworthy event, we can take this triangle and figure out which stars could possibly have seen it and transmitted a response. This gives us a prediction of which stars of those 17 billion to look at and when. So at any given time, there's only a few hundred stars you need to monitor, maybe a few thousand, depending on how far you go. This gives you a prediction of which stars and when. And so even if the signal, even if the lighthouse is really faint and really subtle, you know when the lighthouse is gonna blink because it's in coordination with this big coordinating signaling event. It's kind of a convoluted model, but again, it's good because we can write code to do this. I don't have to go out there and measure a triangle. I don't remember how to measure triangles. Code does this. This is what we invented computers for. So here's one real example. Supernova 1987A. This is the closest supernova that happened in the last 400 years. Big deal happened in 1987 from our vantage point. The information that supernova reached us in 1987 when I was just a little kid. And here is a two-dimensional map, a real map. This is the only real map I've got in this talk. This is the position of 300,000 of the nearest stars. It's in units of parsecs, don't stress about that. You know the units of parsecs? The Kessel run did it in 2012. It's fine. Parsecs just distance, it's like 300 light years. This is a little ball of stars 300 light years away. The blue stars are ones that have seen supernova 1987A. The supernova happened this direction. Like I'm the supernova and the supernova happened this direction. So you can see this curvature here as the light in the supernova is reaching the stars. Something like 52% of the stars, this doesn't add up to one. Somebody did the math wrong. It was me. It's like 48, not 41. This should be 48. So something like half the stars in our neighborhood have seen the supernova, half have not. There's still a lot of stars that haven't even seen this event, right? It was 35 years ago. That's nothing for a star. Our galaxy is over 100,000 light years across. Something happened 35 years ago in our neighborhood is nothing. We gotta wait a little while. We gotta be patient. It's not fair to say we've looked, we didn't see anything. It's not, the news hasn't reached these people yet. And if you draw the cone of people who could have sent a transmission, that's only 7%. That number is correct. This yellow cone here, these are the stars that could have seen the supernova and we could have received their signal. And so we can only eliminate of this 300,000 just near us. We can only eliminate 7% of them. The rest of these stars are fair game and we need to watch them. We need to be monitoring them. Thank goodness we're building an all-sky survey that monitors the whole night sky for other reasons but also for this. There's a lot to search and a lot of opportunities face here. The third example which I think is so rad. In 2017, we discovered the first rock. We called it a comet at the time. It's unclear. It might be a rock. It might be a fragment of a planet. This rock, which was named Oumuamua, came from another star. This is not from our solar system. We call this the first interstellar visitor. The first interstellar asteroid. It came in on this hyperbolic orbit coming down from the plane of the solar system and then pivoted out. We actually saw it here as it was leaving. This is a really rad object. And some people have speculated it could be a spaceship. I don't think it is a spaceship. But some people think it's a spaceship. I don't think it's a spaceship. But it is the kind of thing that came from another star. If there was a spaceship coming, it might take a trajectory like this. And one way to search, well, we know how gravity works. We have that down. We figured that out a while ago. So we know if this thing is just falling towards the sun, if it's just falling and gravity's at work, we know it'll fall towards the sun and then it'll bounce out and it'll head out on its merry way. If the comet is going along following the path that gravity would take it, and then it turns by 90 degrees, that is a really interesting red flag. And one of the things that Meredith talked about, one of the reasons we're stressed about satellites is we want to find comets. We would like an asteroid to not run into Earth preferably, and so we'd like to find them. I don't know what we would do about it, but we'd like to find them to know. And we're watching. We're modeling these orbits. We're watching them. If one of them takes a right turn, that's a huge technostructure. That's a huge sign that something might be happening. This is a cool opportunity and something that's really good for big computers to work on. And so for the last time, I'll say, SETI in the next 10 years, just these three ideas, are mapping parameter space that have never been tried. We've never tried anything like this. We've never had the technology or the computational power or the resources to do anything like this. We're building telescopes for all the other reasons we build telescopes, and we can do this, too. We have strategies that can use the so-called big data, these strategies of changing stars, of coordinated signals, of moving things that these telescopes are going to get us for free. And we just need to go out there and look. And so the search is just beginning. Technost signatures are coming, I hope. The search for them is definitely coming. Thank you.